Due to a difference in temperature and humidity between indoor environments and outdoor environments of a vehicle, fog may occur on the interior surfaces of the windows of the vehicle. The fog formed on the windows screens the visual field of the driver to make it difficult to recognize a preceding vehicle or an oncoming vehicle, and in severe cases, may cause a minor collision with another vehicle or an object due to insecurity of a visual field.
In order to prevent such a risk, generally, when fog is formed on the interior surface of a window of a vehicle, a driver operates an air conditioner for defogging so as to perform a defogging for dry air discharged through an outlet to remove humidity formed on the window.
Such a general defogging system for a vehicle does not include a separate device for defogging, but utilizes a conventional air conditioner system without any change. As shown in a conventional air conditional system for a vehicle, disclosed in a Korean conventional art, a normal air conditioner system is configured to compress refrigerant through a compressor, to radiate the compressed refrigerant through a condenser, to expand the condensed refrigerant, and to flow the expanded refrigerant to an evaporator, thereby cooling air passing through the evaporator. The air, which has passed through the evaporator, is cooled to lower the relative humidity thereof, and thus is discharged as low-temperature dry air. The dry air is introduced into the room, and absorbs humidity in the room, thereby performing a defogging for the room of the vehicle.
However, since even such a conventional technique requires a compressor to be driven for generating dry air, and the compressor is driven by the power of an engine, the fuel efficiency of the vehicle is deteriorated as dehumidification is performed. In addition, since there is a large difference between an indoor temperature and the temperature of air discharged from the evaporator, a rapid change is caused in the indoor temperature, which causes dissatisfactions of customers.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the inventive concept and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.